Elevator arrangement

Abstract

The method of the invention can be used to improve the performance of an elevator system. In the method, the acceleration and/or velocity of at least one door in the elevator system is measured and a dynamic model of the door is created. Using the model, an estimation of acceleration and velocity can be calculated as a function of unknown parameters. From the estimated acceleration or velocity and the measured acceleration or velocity an error function is obtained, and a search is performed in an optimizer to find its minimum value. The unknown parameters corresponding to the minimum value indicate the value of the kinetic parameters of the door at the instant being considered. By utilizing the calculated values of the kinetic parameters, the functions of the doors in the elevator system are optimized separately for each door. Using a genetic algorithm, it is possible to determine, in addition to the unknown kinetic parameters, the operational state of the door closing device as well.

1. A method for improving the performance of an elevator system, said elevator system including at least one elevator, said elevator including at least one elevator door and at least one door operator for opening and closing said elevator door, the method comprising:
 measuring the torque of a door motor moving said at least one elevator door and at least one of the acceleration and velocity of the elevator door; 
 creating for the elevator door a dynamic model incorporating the forces acting on the elevator door; 
 estimating kinetic parameters of the elevator door via the use of the aforesaid measured acceleration or the aforesaid measured velocity and the aforesaid measured torque and the dynamic model of the elevator door; 
 modeling in the dynamic model of the elevator door the acceleration or velocity of the elevator door as a function of one or more kinetic parameters, said parameters being mass of the elevator door, frictional force acting on the elevator door, force caused by the tilt angle of the elevator door and operational state of the closing device; 
 calculating a first error function either as the difference between the measured instantaneous acceleration of the elevator door and the instantaneous elevator door acceleration modeled in the model or as the difference between the measured instantaneous velocity of the elevator door and the instantaneous elevator door velocity modeled in the model; 
 calculating a second error function by squaring the first error function and summing the squared first error functions obtained over a certain time interval with desired weighting coefficients; 
 calculating one or more of the aforesaid parameters by minimizing the second error function; 
 feeding back the calculated parameters to the dynamic model for use in the next calculation cycle; and 
 optimizing the operation of the elevator door via the use of the estimated kinetic parameters to improve the performance of the elevator system. 
 
   
   
     2. A method according to  claim 1 , wherein the acceleration of the elevator door is measured by using an acceleration sensor. 
   
   
     3. A method according to  claim 1 , wherein the velocity of the elevator door is measured by using a signal proportional to the velocity or position of the door, obtained from the door motor. 
   
   
     4. A method according to  claim 1 , wherein the parameters used as input parameters of the dynamic model consist of one or more of the following: acceleration of the elevator door, velocity of the elevator door, torque of the door motor actuating the elevator door, frictional torque of said motor, force factor of the closing spring of the elevator door, and mass of the closing weight of the elevator door. 
   
   
     5. A method according to  claim 1 , wherein, by utilizing the dynamic model of the elevator door, one or more the kinetic parameters of the elevator door are estimated, said parameters being mass of the elevator door, frictional force applied to the elevator door, force caused by the tilt angle of the door, and operational state of the closing device. 
   
   
     6. A method according to  claim 1 , wherein one or more of the kinetic parameters of the elevator door are determined in connection with the start-up of the elevator, and these kinetic parameters are defined as constant parameters in the dynamic model of the elevator door. 
   
   
     7. A method for improving the performance of an elevator system, said elevator system including at least one elevator, said elevator including at least one elevator door and at least one door operator for opening and closing said elevator door, the method comprising:
 measuring the torque of a door motor moving said at least one elevator door and at least one of the acceleration and velocity of the elevator door; 
 creating for the elevator door a dynamic model incorporating the forces acting on the elevator door; 
 estimating kinetic parameters of the elevator door via the use of the aforesaid measured acceleration or the aforesaid measured velocity and the aforesaid measured torque and the dynamic model of the elevator door; 
 using a genetic algorithm for detecting the operational state of the closing device of the elevator door; 
 using in the genetic algorithm a chromosome consisting of genes describing the operation of the closing device, the frictional force acting on the elevator door, and the force caused by the tilt angle of the elevator door; 
 using a squared error function as a goodness value of the genetic algorithm; and 
 using the dynamic model of the door in the determination of the phenotype of the genetic algorithm; and 
 optimizing the operation of the elevator door via the use of the estimated kinetic parameters to improve the performance of the elevator system. 
 
   
   
     8. A method according to  claim 7 , wherein one or more of the control parameters of the controller of the door motor actuating the elevator door are determined by utilizing the kinetic parameters of the elevator door, said control parameters being gain of the controller and controller feedforward torque value. 
   
   
     9. A method according to  claim 7 , wherein the velocity profile of the elevator door is determined by using one or more auxiliary parameters, said auxiliary parameters being maximum allowed instantaneous kinetic energy of the elevator door, maximum allowed average kinetic energy of the elevator door, traffic condition of the elevator system, passenger-specific identification data. 
   
   
     10. A method according to  claim 7 , wherein the estimated kinetic parameters of one or more elevator doors are stored in the elevator system, and the kinetic parameters to be used in the optimization of the functions of the elevator door are selected from the said stored parameters on the basis of an external selection signal. 
   
   
     11. A method according to  claim 10 , wherein the external signal used for the selection of kinetic parameters is a signal indicating the destination floor, said signal being generated in the elevator control system or in the group control of the elevator system. 
   
   
     12. A method according to  claim 10 , wherein the external signal used for the selection of kinetic parameters is a signal generated by a floor detector moving with the elevator car. 
   
   
     13. A system for improving the performance of an elevator system, said elevator system including at least one elevator, said elevator including at least one elevator door and at least one door operator ( 61 ) for opening and closing said elevator door, the system comprising:
 a measuring unit that measures the torque of a door motor moving said at least one elevator door and at least one of the acceleration and velocity of the elevator door; 
 a dynamic model of the elevator door, incorporating the forces acting on the elevator door 
 an estimation unit that estimates kinetic parameters of the elevator door using the measured acceleration or the measured velocity and the measured torque of the motor moving the elevator door and the dynamic model of the elevator door; 
 an optimization unit that modifies the operation of the elevator door based on the estimated kinetic parameters to improve the performance of the elevator system; 
 a modeling unit that models the acceleration or velocity of the elevator door in the dynamic model, said acceleration or velocity being defined as a function of one or more kinetic parameters of the elevator door, such parameters being mass of the elevator door, frictional force acting on the elevator door, force caused by the tilt angle of the elevator door and operational state of the closing device; 
 a first error calculator that calculates a first error function, said error function being obtained either as the difference between the measured instantaneous acceleration of the elevator door and the instantaneous elevator door acceleration modeled in the model or as the difference between the measured instantaneous velocity of the elevator door and the instantaneous elevator door velocity modeled in the model; 
 a second error calculator that calculates a second error function, said second error function being obtained by squaring the first error function and summing the squared first error functions obtained over a certain time interval with desired weighting coefficients; 
 a first optimization unit that minimizes the second error function, thereby determining one or more of the kinetic parameters of the elevator door; and 
 a first feedback unit that passes the calculated parameters to the dynamic model for use in the next calculation cycle. 
 
   
   
     14. A system according to  claim 13 , wherein the system further comprises a signal a d  proportional to acceleration as a means of measuring door acceleration. 
   
   
     15. A system according to  claim 13 , wherein the system further comprises a signal v d  proportional to the velocity or position of the door, obtained from the door motor and used as a means of measuring door velocity. 
   
   
     16. A system according to  claim 13 , wherein the system further comprises means for determining one or more parameters of the dynamic model ( 22 , 32 , 42 ) via actions which are measurement of elevator door acceleration, measurement of elevator door velocity, measurement of the current of the door motor moving the elevator door, determination of the torque coefficient one of the door motor, determination of the frictional torque of the motor, determination of the force factor of the closing spring of the elevator door, and determination of the mass of the closing weight of the elevator door. 
   
   
     17. A system according to  claim 13 , wherein the kinetic parameters to be estimated in the system are one or more of the following parameters (P): mass of the elevator door, frictional force applied to the elevator door, force caused by the tilt angle of the door, and operational state of the closing device. 
   
   
     18. A system for improving the performance of an elevator system, said elevator system including at least one elevator, said elevator including at least one elevator door and at least one door operator ( 61 ) for opening and closing said elevator door, the system comprising:
 a measuring unit that measures the torque of a door motor moving said at least one elevator door and at least one of the acceleration and velocity of the elevator door; 
 a dynamic model of the elevator door, incorporating the forces acting on the elevator door; 
 an estimation unit that estimates kinetic parameters of the elevator door using the measured acceleration or the measured velocity and the measured torque of the motor moving the elevator door and the dynamic model of the elevator door; 
 an optimization unit that modifies the operation of the elevator door based on the estimated kinetic parameters to improve the performance of the elevator system and; 
 a third optimization unit that; 
 uses a genetic algorithm to detect the operational state of the closing device of the elevator door;
 uses one or more kinetic parameters in the genetic algorithm as genes of a chromosome, said parameters being operation of the closing device, frictional force applied to the door and force caused by the tilt angle of the door; 
 a squared error function ( 44 ) as a goodness value of the genetic algorithm; and 
 uses the dynamic model of the door in the determination of the phenotype of the genetic algorithm. 
 
 
   
   
     19. A system according to  claim 18 , wherein the system further comprises a control parameter determination unit that determines the control parameters of the controller of the door motor moving the elevator door, said control parameters being gain of the door motor and controller feedforward torque value. 
   
   
     20. A system according to  claim 18 , wherein the system further comprises: a velocity profile determination unit that determines the velocity profile of the elevator door by using one or more auxiliary parameters, said auxiliary parameters being maximum allowed instantaneous kinetic energy of the elevator door, maximum allowed average kinetic energy of the elevator door, traffic condition S t  of the elevator system, passenger-specific identification data S p . 
   
   
     21. A system according to  claim 18 , wherein the system further comprises a memory that stores the kinetic parameters of one or more elevator doors to the elevator system, the kinetic parameters to be used in the optimization of the functions of the elevator door being selectable from among the said stored parameters by using an external selection signal. 
   
   
     22. A system according to  claim 21 , wherein the external selection signal for selecting the kinetic parameters is a signal indicating the destination floor, which signal has been generated in the elevator control system or in the group control of the elevator system. 
   
   
     23. A system according to  claim 21 , wherein the external selection signal for selecting the kinetic parameters has been generated by a floor detector moving with the elevator car.